The present invention relates to a dental instrument delivery system which moves the instrument between an inaccessible stored position and a ready position. At the ready position the instrument is held so it can be grasped by the dentist. More particularly, the present invention relates to a delivery system which delivers the instrument into the open hand of the dentist whereby the instrument, as it approaches the ready position travels downwardly through a substantially vertical path of travel into the open hand of the dentist as opposed to traversing in a horizontal direction across the dentist's hand.
A dental unit commonly supports a plurality of dental instruments requiring a source of utility supply, such as pneumatic and electric drills, syringes and suction equipment. In such units, it is desirable to locate the instruments side by side in an array with the smallest possible spacing between adjacent instruments so as to maintain the overall width of the unit as small as possible.
However, bunching the instruments too close together makes it difficult for the dentist to select and grasp a particular instrument. This is particularly true if the instruments are so close together that the user cannot put his hand between adjacent instruments.
The problem is solved to some extent by individually supporting instruments close together in a stored or inaccessible position. When the dentist desires to use a particular instrument, the selected instrument together with its support is moved from the array to a readiness position. At the readiness position, the selected instrument and its support stands out from the array so that it may be easily grasped by the dentist. With this arrangement, the dentist merely grasps the instrument and pulls it from its support to a point of use. After use, the dentist can return the instrument to its support for later use as desired. When the instrument is no longer needed, the instrument and its support is moved from the readiness position back to the storage position.
In one delivery system as shown, for example, in German Pat. No. 29,876 the instrument stored within the unit is pushed into the readiness position by an ejection spring operated by pressure on a slide bar, the bar also acting as the means for selecting the particular instrument desired. When the procedure is complete, the instrument is returned by pushing on the slide bar to move the instrument and its nest against the force of the ejection spring toward the stored position.
U.S. Pat. No. 3,802,736 provides a system wherein the instrument is returned to its stored position under the restoring bias of a spring acting on the instrument feedline. In this situation, however, the bias of the spring operates on the feedline while it is being drawn out to its full length. Thus, the user must overcome this bias when moving the instrument nest to a readiness position and when withdrawing the instrument from its nest.